Whenever cable companies feel threatened, they form a joint venture. The latest is called Project Canoe, an effort by all six major cable companies in the U.S. to deliver targeted TV ads to viewers through their set-top boxes. The NYT reports:

Collectively, the cable companies will initially put about $150 million behind the effort in order to build a national service that can sell targeted advertising across all six cable systems.

The cable companies may control the set-top boxes, but they only collectively control about $5 billion of the $70 billion spent each year on TV ads. Most of those are local spots. With better ad targeting through Project Canoe the cable companies hope to triple their take to $15 billion. But that may be wishful thinking.

Of course, all of this is a reaction to Google, which already is testing its own TV ads on EchoStar’s Dish Network (no satellite companies are part of Project Canoe). Just last week, some Google TV Ad beta testers were able to start buying TV ads through AdWords as part of their regular advertising campaigns. In other words, they can buy search ads on Google, contextual online ads across the Web, and TV ads on Dish all through the same Google interface.

Through its partnership with EchoStar, Google’s software is on millions of set-top boxes, anonymously monitoring everything viewers do while watching TV. Advertisers in the beta can bid on ad slots by geography, demographics, day, time, and network. Google gives them data on how many people saw their TV commercials, how long they watched the ads, and at what point they lost most of their viewers. These are similar to the same sort of detailed reports advertisers can get on the Web. As I suggested last November:

Any new video ad unit that starts to gain traction on the Web could be ported over to regular TVs—clickable overlays, contextual video ads, unobtrusive sponsorship icons. Why not even let viewers program their own ads with a laundry list of categories and companies to choose from? They might actually watch them.

When it comes to advertising, Google is not shy about stating its ambitions. “We are confident we are going to revive the television advertising industry,” says [Google TV’s Vincent] Dureau, “by bringing new advertising to it.” Already, Google is trying to make TV ads more relevant, easier to target, and cheaper to deploy. As a result, Google thinks it can attract more ad dollars from smaller businesses that may not have been advertising on TV before.

The fact that the cable companies are creating their own advertising tracking software does not bode well for Google’s TV ad project ever making it beyond satellite-TV networks. Why should they hand over to Google a cut of their ad revenues? But giving Google the high hat will just make it more likely that Google will go ahead with its own secret set-top box project. An Android-like open-source set-top box could end up being a lot more disruptive to the cable companies’ business than simply letting Google in the front door.

AdWords already has a strong presence among the very same small- and medium-sized businesses the cable companies are going after. The big opportunity here is bringing more local ads to TV because one of the most effective ways to target TV ads is (still) by geography. Just ask Spot Runner, which already lets small, local businesses buy TV ads over the Web and is planning on combining that with online ad buys as well.

The cable companies have an advantage in that they own the set-top boxes required to make ad targeting work on TVs. They are now paddling fast to catch up. But there are also some mighty currents working against them. This is not just about putting software on set-top boxes, it is about creating the right software that can make TV ads more relevant. Who is more likely to do that: Google or a multi-headed joint venture? Then the cable companies will have to create their own ad network as well, which will compete with the TV networks their business relies on. They’d better put that canoe in the water and start paddling fast.